Chief Accuser: How Credible Is Clarke?

When Richard Clarke appeared before the 9/11 commission last week, Republican panelist James Thompson abruptly challenged him to reconcile his damning book with a contradictory pro--Bush Administration statement. "We have your book, and we have your press briefing ... Which is true?" Is Clarke, terrorism czar for the past two Administrations, a truth teller or a lying opportunist?

Clarke's timing is indeed convenient. Against All Enemies came out the week he testified before the commission. If he receives a typical royalty rate, he would make at least $1.8 million from sales. But Clarke is not easily caricatured. He just ended a...